586 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
6 
SEPT. 
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OCT. 
r- 
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Fig. 15.—Comparison of the number of migrating larvae recovered 
daily in the fall of 1922 with the mean night temperatures. The graded 
scale to the left indicates number of larvse and applies to the blocked-in 
area. The scale to the right applies to the mean night temperatures 
shown by the broken line AA. Blank spaces in the record of number of 
larvae mean that traps were not examined on those days, the record 
for the day immediately following showing the migration of two nights. 
